Default IP table modification causes reboot in rooted stock 4.2.2 MF9!

Title say's most of it, but I have a rooted 4.2.2 stock MF9, TWRP recovery, with kernel version 3.4.0-953334 which re-boot's if I try to manually or through other means attempt to change the IP table. Installed and ran Android Firewall by jtschohl and when I tried to apply rules device re-booted! Tried with Avast firewall and received same results. jtschohl was nice enough to respond (very quickly I might add) to the crash report I sent and pointed out that a particular Samsung build had a kernel issue that caused this problem. I would not have been smart enough to figure this out on my own - true.
I have spent a few hours reviewing at XDA posts about updating to newer 4.4.2 (or other) and it seems like a very problem laden process - too many reports of excessive battery drain, lock screen, voicemail, wi-fi, etc issue's that I simply don't have on my current build. Currently with the Samsung app's I don't need frozen via Titanium, a custom launcher, Llama, and a few other changes I have a very stable, very fast, very reliable phone with the exception of not being able to implement a firewall (which I would really like for a couple of app's who talk too much!), evidently due to a kernel issue.

Question is - can I update the kernel to one without this IP table/re-boot issue without loosing stability, root, my current app's/data? I'm happy staying with 4.2.2 MF9 - no bootloader issue's introduced in 4.3 and beyond etc. - so that is my level of satisfaction with my current set-up. It also obviously reflects my level of competence and unwillingness to potentially screw up my phone - especially a boot loop type issue - which I encountered 1 time out of 7 devices I had otherwise successfully rooted over the last 2 years. My wife's S4 is at exactly the same level and has the identical issue BTW - mentioned since in my search I didn't seem to find this IP table issue discussed?